Vulcanization of rubber and similar materials.



DOUGLAS FRANK T'WIEES, SUTEGIE CQLDFIELD, EIG'GLAND, ASZSIGEZI'OR T0 THE @UNLQP fiUIiBER i'lOMPilNY, LIMITED, OF WESTMINSTER, LQNDQH,

' ToaZZ whom it may concern:

Be it lmown that l, DOUGLAS FRANK 'lwrss,

a subject of the King of Great Britain, re

terials and more specifically to the facceleration of the vulcanizing action by the em 'terioration of the rubber.

ployment of a strongly basic substance.

vulcanization acceleratorsoi organic na ture have been proposed and used for several years and with some few exceptions these accelerators are strongly basic sub stances, and. the more effective mineral accelerators such as litharge, magnesia ancl lime are also basic compounds.

It has also recently been found that a craps rubber which, when freshly coagulated, has been soaked f with a solution of caustic soda, vulcanizes raphlly but.the suggestion that such a treatment of rubber might prove of practical value was with orawn owing to the danger of causing l9- Caustic alkali (sodium or potassium hydrosid) can, however, be satisfactorily employed as an accel" orator if used in conjunction with other i 0 i I p I substances and in accorclance with this 1nvention an accelerator is employed consitting of a solution of caustic alkaliinan organic compound, such as glycerolor glycbl, which can without decomposition absorb or dissolve the alkali anrl so produce a uniform homogeneous mass.

v Glycerol or glycol are polyhydric alcohols and are examples of hydroxy-organic compounds which are found to be specially suitable for the present purpose. By adding the alkali to the rubber mixing in the manner described, the uniform distribution of the alkalithroughout the mass can be insured,

Specification of letters Eatent.

.Patenteii July 9, truth.

Application filec'i January e, Isle. Serial No. moses.

' anti the rate of vulcanization of the mixing is greatly acceleratecl.

If glycerol is heated to about 175 C. to expel superfluous water the hydroxicl can be dissolved. and on cooling a viscous solution of alkali glyceroxid is obtained. Potassium liyclroxid is found usually .to' be somewhat preferable for this method. One part of potassium hydroxicl may be used with three to four parts by Weight of glycerol although the proportions may be varieol much more widely. One or two per cent. of such'a solution will mix into rubher uniformly and, as the solution has a low vapor pressure, there is no tendency to proflucc porosity of the rubber as may occur with many organic acceleratlu's. It is found that a mixture of rubber with 5 per "What I claim and desire to secure by lDetters Patent of the United States is l. A. method of accelerating a vulcanizing I process which consists in aclding to the rubber mixing an accelerator comprising caustic alkali dissolved in a hydroxy-organiccompound forming a solvent which is not decomposed by the alkali.

2;. A. method of accelerating a vulcanizing process which consists of adding to the rubber mixture an accelerator comprising caustic alkali. dissolved. in a polyhyilric alcohol. v

3. A method of accelerating a vulcanizing process which. consists in aclcling to the rubber mixing an accelerator comprising caustic alkali dissolved in glycerol or glycol.

nouonas ensue: ssues. 

